CHAPTER 1
Cancer Diagnosis and Treatment

Doctors have always recognized that every patient is unique, and doctors have always tried to tailor their treatments as best they can to individuals. You can match a blood transfusion to a blood type. That was an important discovery. What if matching a cancer cure to our genetic code was just as easy, just as standard?

—President Barack Obama (January 30, 2015; Precision Medicine Initiative)

A cancer genetic counseling session often begins with hearing the patient’s cancer story: the symptoms that led to the suspicion of cancer, the way in which the diagnosis was made, and the subsequent treatment regimen. This chapter describes the process of making a cancer diagnosis, the systems used to classify tumors, and the current strategies for cancer treatment. The chapter will also briefly touch on the risk factors for cancer as context for a genetic counseling session.

1.1. The Diagnosis of Cancer

This section provides the information necessary to understanding a cancer diagnosis, from how cancer is diagnosed to the nomenclature used to describe the tumor and the treatment options that are available.

1.1.1. Cancer Detection

A diagnosis of cancer often begins with a worrisome symptom or problem on a medical intake or screening test. For example, a physical exam may reveal swollen lymph glands or unusual tenderness. A routine screening test, such as a colonoscopy, cervical Pap smear, or blood test, may identify the presence of atypical cells or an unusually high number of cells. A blood specimen that shows a dramatically high count of “blasts” (immature white blood cells) in a young child may point to the presence of acute lymphoblastic leukemia.

In many cases, patients have noticed warning signs of cancer (see Table 1.1). They may note a new physical finding, such as a breast lump, or they have health problems that are not abating over time (such as a persistent cough) or even getting worse (such as bleeding after a bowel movement).

People are more likely to experience symptoms or warning signs if their tumor:

• Is pressing on neighboring tissue and causes pain
• Is interfering with the functioning of normal tissue
• Has invaded the blood vessels to cause abnormal bleeding
• Has grown large enough to be palpated

A malignant tumor can be present for months, even years, before it is detected. The reasons why cancer detection can be so difficult are presented in the following sections.

1.1.1.1. Lack of Warning Signs

There may be no physical symptoms that signal the presence of early‐stage cancer. Observable signs of cancer are more likely to be noticed as the cancer progresses. Sometimes, this means that the hallmarks of cancer, such as a lump, bleeding, or pain, indicate a malignancy that is already in an intermediate or advanced stage. However, most of the time, common symptoms are unrelated to cancer. If symptoms persist, they should be evaluated.

TABLE 1.1. General Signs and Symptoms of Cancer

Source: American Cancer Society (accessed 2021).

Fatigue or extreme tiredness that doesn’t get better with rest Weight loss or gain of 10 pounds or more for no known reason Eating problems such as not feeling hungry, trouble swallowing, belly pain, or nausea and vomiting Swelling or lumps anywhere in the body Thickening or lump in the breast or other part of the body Pain, especially new or with no known reason, that doesn’t go away or gets worse Skin changes such as a lump that bleeds or turns scaly, a new mole or a change in a mole, a sore that does not heal, or a yellowish color to the skin or eyes (jaundice) Cough or hoarseness that does not go away Unusual bleeding or bruising for no known reason Change in bowel habits, such as constipation or diarrhea, that doesn’t go away or a change in how stools look Bladder changes such as pain when passing urine, blood in the urine, or needing to pass urine more or less often Fever or night sweats Headaches Vision or hearing problems Mouth changes such as sores, bleeding, pain, or numbness

1.1.1.2. Imperfect or Lack of Screening Methods

To be effective, screening tests need to be easily performed, affordable, and accurate in detecting disease cases while limiting the number of false positive tests. The cancers must be detectable at earlier, more curable, stages and must occur at a frequency that justifies population screening. For example, a Pap smear is an effective screening test for cervical cancer, because it is a fairly common disease and early diagnosis has been shown to make a significant difference in survival. Cancers such as ovarian cancer have no known effective screening methods in detecting cancer reliably, although much work is being done in this area. Screening tests for less common forms of cancer are generally offered only to those known to be at high risk.

1.1.1.3. Elusive Premalignant Cells

Few organs can be readily and repeatedly sampled, which makes it difficult to monitor the organs for malignant or (even better) premalignant cells. At this point, only a few screening tests reliably detect premalignant cells, with colonoscopies being one of the best examples.

Cutting edge research is looking into the development of tests for very early markers of cancer through blood tests (see Chapter 8).

1.1.2. Making the Diagnosis of Cancer

The workup for cancer typically begins when other more likely explanations have been ruled out. For example, the differential diagnosis of frequent headaches includes vision problems, allergies, and stress. More serious possibilities, such as a brain tumor or neurological problem, are less likely to be entertained at the outset because of their relative rarity. Because of this, a common theme among members of families with hereditary cancer syndromes is that signs of cancer were initially ignored or downplayed by their providers.

The method by which the cancer will be identified depends on the tumor type (see Table 1.2). The presence of cancer may be suggested by physical exam, imaging studies, specialized blood tests (see Table 1.3 for some common tumor markers detected in blood), or invasive procedures. Except in rare cases, biopsy is required to make a definitive diagnosis. For example, the diagnosis of pancreatic cancer may start with a symptom of weight loss and subsequent imaging, but it is the biopsy and subsequent pathologic analysis that will confirm the diagnosis.

TABLE 1.2. How Cancer is Diagnosed

Source: Adapted from National Cancer Institute, How Cancer Is Diagnosed.

LAB TESTS BLOOD, URINE, BODY FLUID IMAGING TESTS CT SCAN MRI NUCLEAR SCAN PET SCAN ULTRASOUND X-RAYS BIOPSY WITH A NEEDLE WITH ENDOSCOPY WITH SURGERY

TABLE 1.3. Some Common Tumor Markers Used in Diagnosis and Assessment of Cancer

Source: Adapted from National Cancer Institute, Tumor Markers in Common Use.

Tumor Marker	Type of Sample	Cancer

CA 19‐9

Blood

Pancreatic, gallbladder, bile duct, and gastric cancers

CA‐125

Blood

Ovarian cancers

Calcitonin

Blood

Medullary thyroid cancer

CEA

Blood

Colorectal and other cancers

Chromogranin A

Blood

Neuroendocrine tumor

Prostate‐specific antigen (PSA)

Blood

Prostate cancer

Individuals will be referred to a medical oncologist either when the suspicion of cancer has been raised or following the initial diagnosis. As with most medical specialties, clinical oncology is divided into many subspecialties. Other members of the cancer care team include surgeons, radiologists, radiation oncologists, pathologists, and mental health professionals; the care of individuals with cancer requires a multidisciplinary team.

Cancer can be a high‐burden disease on both patients and their families. Learning that one has cancer can engender feelings of shock, anger, intense sadness, and extreme anxiety. As patients enter cancer treatment, they may need to make major adjustments in their family responsibilities and workload. At many cancer centers, patients and their families have the opportunity to meet with a social worker or psychologist. Patient support groups may also be helpful.

1.1.3. Cancer...